Four years after its predecessor comes Sentinel 4: Dark Star, a sturdy Tower Defense game that might lack the finesse of the modern era but is still pretty enjoyable.

Sentinel 4: Dark Star is packed full of features and complexities, but it lacks one notable thing - graphically, it's really not that special to look at. While I've always been one for going for substance over style, it's still noticeable that Sentinel 4: Dark Star isn't a looker. There's also the issue that Sentinel 4: Dark Star carries a premium price tag as well as some micro transactions. It's possible to dodge these, but no one could be blamed for being a bit irritated at the proposition.

Look past all that though, and discover that Sentinel 4: Dark Star is a pretty varied Tower Defense game. Its 26 levels are plentiful and long lasting, while an Endless mode rounds things off nicely. There are also the four difficulty levels to choose from, steadily adding to the challenge.

Most importantly though is the plethora of upgrades on offer. Each level of Sentinel 4: Dark Star can be quite involved, with placed towers leveling-up both through regular attacks as well as permanent upgrades. Even the walls can be upgraded. Some units can be placed in lanes as well as alongside, plus there's the mighty Sentinel with its own set of abilities and the chance to strengthen nearby units. Refreshingly, for a Tower Defense game, no one's safe either as enemies can attack towers.

The main issue here is that Sentinel 4: Dark Star doesn't do a great job of explaining everything. Instead, you're left to figure things out for yourself. As one of the more complex Tower Defense games, that might prove off-putting for some but it'll be worth it.

Sentinel 4: Dark Star might not be quite the revolution that some were expecting after its earlier incarnation, but it's still an excellent example of the genre.

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